| Abstrakt: |
Wear is one of the most common problems in heavy equipment components. Recently, there were several cases of such problem in different locations in Indonesia. Wear occurred at the bushings on the undercarriage of heavy equipment, which acted as the connector between chains. The events occurred at a high rate, and there are differences in rate for each area of operation. The objective of this research was to understand the wear mechanism of worn bushings and determine the relationship between soil types and wear level. Laboratory characterization of bushing specimens and three-body abrasion test which referred to ASTM B611 were conducted. Characterization of worn specimens involved visual examination, chemical composition characterization, microstructure observation, measurement of phase thickness, hardness test and SEM observation. A three-body abrasion test was carried out using a machine test developed specifically for this study. Wear initiated at the contact area between bushing, sprocket and soil due to friction. The contact produced shear stress and compression stress on the bushing. Due to shear stress exceeding shear strength, the surface of the bushing underwent plastic deformation. Wear resistance test in varying soil types measured the total mass reduction of specimen. The soil types were, in order of highest to lowest mass reduction: plastic soil (75% silica), plastic soil (60% silica), non-plastic soil (80% silica) and non-plastic soil (70% silica). In non-plastic soil type, higher friction speed resulted in a greater mass reduction of specimen. However, in plastic soil, there was no observable connection between speed and mass reduction. Additionally, the mass reduction of specimen in non-plastic soil tended to be linear over time. [ABSTRACT FROM AUTHOR] |
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